1. Field of the Invention
The present invention relates to an electrode arrangement for a coating device with a fixed first electrode and a second movable electrode, whose principle surfaces are opposite each other, wherein the second electrode may be moved along a plane parallel to the opposite principle surfaces.
Moreover, the present invention relates to a corresponding coating device for use in plasma-enhanced chemical vapour phase deposition with a corresponding electrode arrangement.
2. Prior Art
Plasma enhanced chemical vapour deposition (PECVD) is known from the prior art and is widely employed in different applications for coating or modifying surfaces. For applications involving the coating of architectural glazing and also the manufacture of thin-layer solar cell modules, it is necessary to apply large-surface coatings of very high quality in terms of the homogeneity of the applied coating.
To be able to effect a corresponding homogeneous coating, it is necessary that, especially where the electrodes have large surface areas, the conditions or properties with respect to the electrodes are homogeneous across the electrode surfaces. This applies not only to the potential distribution or the distribution of the electric field, but also to the temperature distribution and the distribution of the materials in the form of reaction gases that are needed for the chemical vapour phase deposition.
Accordingly, the use of so-called showerhead electrodes is known from the prior art wherein the electrode surface has a plurality of outlet openings through which gaseous reaction substances can be introduced into the coating space or, in the case of corresponding plasma-enhanced CVD coating, into the plasma space. This ensures that the gaseous reaction products are distributed over the electrode surfaces and thus over the coating surface as uniformly and thus as homogeneously as possible.
For the purpose of uniform temperature distribution at the electrodes, the prior art also provides corresponding heating and/or cooling devices by means of which a homogeneous temperature distribution can be set at the electrodes. However, in connection with showerhead electrodes, problems arise, namely the provision of corresponding gas distribution spaces is observed to lead to poor temperature conduction in the electrode.
For the purpose of obtaining a homogeneous coating, DE 10010016 C1 proposes that a reaction chamber and a purging chamber be additionally provided in a vacuum chamber, wherein the reaction chamber may also be formed as a shield that is at the same potential as the substrate carrier or the electrode which is formed by the substrate carrier.
DE 39 18256 A1 proposes a shield in a PECVD method as well.
However, these prior art solutions have disadvantages in terms of a high constructive effort or other desired properties.